


gaster

by I_Write_Sans_Not_Tragedies



Series: learn to live [2]
Category: Undertale (Video Game)
Genre: Hurt/Comfort, Underfell, learn to live, mentions of abuse, underswap - Freeform
Language: English
Status: In-Progress
Published: 2016-04-01
Updated: 2018-04-01
Packaged: 2018-05-30 13:26:02
Rating: Mature
Warnings: No Archive Warnings Apply
Chapters: 3
Words: 7,269
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/6425755
Author URL: https://archiveofourown.org/users/I_Write_Sans_Not_Tragedies/pseuds/I_Write_Sans_Not_Tragedies
Summary: <blockquote class="userstuff">
              <p>Red and his father are living with the Underswap brothers now, and even though Red is adjusting quickly, Gaster is not so fortunate. Sans is determined to help him however he can.</p>
            </blockquote>





	1. Chapter 1

**Author's Note:**

> not sure what you can expect from this, it's mostly just exploring what happened to underfell gaster since i didn't touch on that in the main fic. there will be multiple chapters

Red settled in quickly. Until renovations could be made, he stayed in Sans’s room, sleeping on a cozy mattress that Alphys had found at the dump. After the first week of talking and relaxing, he’d talked to Muffet about getting a job and worked part time washing dishes for her. 

Gaster, on the other hand, did not fare so well. It made Sans very sad to see the older skeleton jump when he entered a room, or shrink away from him in fear when he got excited and raised his voice a little. He tried very hard to make the frightened skeleton as comfortable as possible, but even after Papyrus had forced him to take his bedroom, he was still very much afraid of anything that moved.

Papyrus and Red were working. It was a quiet Tuesday morning, but Sans had already been up for a couple of hours. Gaster was still sleeping- Red told them of how bad things had been for the poor doctor after he and Papyrus had left back in their own timeline, and it made Sans all the more careful to be considerate and understanding of the skeleton’s condition.

He knocked gently on the door to his brother’s room.

“Dr. Gaster? I made breakfast, if you’re hungry,” he called gently. 

There was no response. Sans quietly turned the doorknob, wondering if he was still asleep but worrying because Gaster was a very light sleeper, and found that the skeleton wasn’t in his bed.

“Gaster?” he asked. The room was dim, but he saw the white bones of the tall skeleton as he leaned against the closet door, knees drawn up to his chest. He was still in his night clothes.

The man was staring into space with small pinprick eyes. Sans stepped into the room but he didn’t look up. His breathing was quick and he was shaking.

“Gaster? Are you alright?” Sans asked, moving closer but giving the man his space. “It’s morning, sir.”

Sans waved his hand, and the movement made Gaster come out of his trance and jump. He pressed himself to the door.

“Sir, it’s alright. It’s just me,” Sans said softly.

Gaster seemed to recognize his voice and his body lost its tension. He looked away, but his thin hands with ragged holes were shaking. Sans realized the monster was crying.

“It’s alright, sir. Do you want me to leave?” 

Gaster began to reach out a hand before he stopped. The poor man. Sans’s heart twisted in pain as he watched the broken monster move his hands.

_ “I am sorry.” _

“Sir, it’s alright. There’s nothing to be sorry about. Do you need anything? Red already left for work, but I can call him if you want him to-”

_ “No, I am alright. I…” _ Gaster’s hands faltered and he looked away.  _ “I am sorry.” _

Sans frowned. “Would it be alright if I came over? Having people around makes me feel better when I have nightmares.”

Gaster looked at the short skeleton for just a second before he averted his eyes. He nodded.

Sans slowly walked over and took a seat beside Gaster. He left some space between them, but put a gentle hand on his arm.

“It’s alright to be scared, sir,” Sans said. “You and Red have been through some very difficult things, things that I probably couldn’t understand. But, if you need somebody to talk to, I’m here. My sign language is a little rusty, Papy was always better at it than I was, but I’ll do my best!”

Gaster looked at Sans for a moment. His dark eyes were still wet with tears. Sans patted his arm and gave him a smile.

“How about you come down and eat something- you’re just skin and bones!”

Gaster cracked a watery smile and Sans glowed. “That’s better,” he said as he stood and offered Gaster his hand. “Let’s get some meat on those bones!”

The much taller monster accepted Sans’s hand and was gently hauled to his feet. 

_ “That is rather morbid,”  _ he signed, wiping away the remnants of tears from his face.

“You’re right… you don’t want to know how many times Papyrus has made that joke. It’s probably approaching the triple digits.”

_ “Sans is fond of skeleton joke as well.” _

“He and my brother are a handful. When he was here before he called me Pansy Sansy one time, and Papy has been calling me that ever since.  It’s demeaning!”

Gaster smiled as he followed Sans down the stairs. 

 

Much to Sans’s delight, Gaster did not escape back to his temporary room when he was done eating. He sipped the coffee Sans had made him and sat at the table, staring at the wall.

Sans cleaned up the kitchen in the meantime. He would poke his head out to check on Dr. Gaster, to make sure he was alright. He wished he could do more for the skeleton- like give him a big hug and tell him he’d be alright and shower him in kisses and desserts- but he figured that would do little for their slow-building relationship.

When the dishes were clean and put away, Sans walked out and took a seat at the table along with his charge. Gaster glanced at him before staring down into his drink.

“Do you want anymore coffee, sir?” Sans asked as he sat his phone down on the table. “We have tea, too. And hot chocolate.”

_ “I am fine, thank you,”  _ Gaster signed.

“Do you want to talk about it?” Sans inquired gently.

Gaster looked away and Sans saw his abused hands tighten around his cup before he drew them away again.

_ “It is not pleasant. I will be alright.” _

“Well, I assumed it wasn’t very pleasant, but the offer still stands. Have you talked to Red about it?”

_ “Vaguely. Not in detail.” _

“Talking about it usually helps. If you’re comfortable with it, I mean. Just know that, whatever happened, it won’t happen again. You’re safe now, sir. If you’d let me, I’d like to earn your trust.”

Sans stared at him with big eyes. Gaster looked back, his own so dark and tired. His gaze drifted back to the table, but eventually his hands moved.

_ “I used to be able to speak,”  _ he signed. He lifted his hand and gently pulled the top of his turtleneck sweater down- Sans had never seen his neck before. He stifled the gasp that threatened to escape him as he saw the bone there- scarred and crisscrossed with marks and wounds. 

“Oh my gosh… sir, I’m sorry,” Sans said quietly. Gaster didn’t meet his eyes as he covered himself again.

_ “It is not your fault. The King recognized my weakness and took me as his own. I… I do not know what it is like, to be free. I am sorry if I behave strangely.” _

“Oh no, sir, it’s alright. I understand- I mean… no, I don’t, not in the way that you do. But… I think it’s pretty normal to be hesitant about believing you’re actually safe if you’ve been not-safe for so long.”

_ “Sans is…”  _ Gaster shook his head.  _ “Red, rather. He is the only one to have shown me any kindness in our world. When our weapons project backfired, I… I assumed he would resent me for what I’d done. But he does not.” _

Sans looked down for a moment. “He told us a little about that when he was here a long time ago. My brother and I can shapeshift as well, but it happened naturally. He didn’t seem to blame you for what had happened- he mostly blamed Papyrus. His Papyrus.”

Gaster said nothing else. He had a look of deep sadness on his face that Sans would never truly understand. 

“I just want you to know that you’re safe here, doctor. Red cares about you a lot, and I do, too. If you ever need anything, please don’t think twice about telling me, alright?”

_ “You are kind. Thank you.” _

“I don’t have work today, would you like to watch some TV? Red tells me that you’ve got some kind of masochistic robot guy, but we just have Napstablook. He’s a cool DJ robot. Papy and Red don’t seem to like him that much, though…”

_ “That would be nice,”  _ Gaster signed. 

Sans grinned. “Awesome! I’ve also got some video games that Undyne lent me, too, if you wanted to check those out later. She’s nice, a little shy and soft-spoken, but she makes cool robots and stuff, so that’s neat.”

Gaster nodded. Sans was content with his progress as they went to watch some television.


	2. Chapter 2

The second morning it happened, Sans found Gaster still in his bed. He held his head in his hands and his eye burned with violent blue magic as rasping pants escaped him.

“Gaster,” Sans said as he walked beside the bed and gently touched his shoulder. “Gaster, it’s alright, it’s just a bad dream.”

The man said nothing at all. His eyes slowly went to Sans, but they were wide and unblinking and he didn’t seem to really understand what was happening.

“Dr. Gaster, it’s just me. Sans. Remember?” the small skeleton asked as he gently rubbed the monster’s arm to ground him. “You’re fine, it’s just a nightmare.”

Gaster was slow to come out of it. Two months had passed since they’d arrived. The renovations were being built but weren’t complete, and Sans had worked on getting to know Gaster better.

When Gaster finally seemed to come to, his magic faded and the two were left in the dim lighting of Papyrus’s old bedroom. Gaster was breathing heavily, but he allowed Sans to gently remove his hands from his skull.

“Are you okay?” Sans asked. “Do you need anything?”

_ “No. I am fine.” _

__ Sans frowned. Gaster’s hands were shaking and his eyes were still wide. Sans took a seat on the edge of the bed. He didn’t have much to say, but he kept his hand on Gaster’s arm, gentle and unobtrusive. 

In the weeks that had passed, Sans and Gaster had bonded to some extent. Gaster had yet to open up to anybody aside from Red, and even if Sans understood, he wished he could help Gaster more. 

_ “Do you have nightmares about what Red did to you?” _

__ The question was so sudden and Gaster signed it so fast that Sans barely understood. When he did, his soul gave a painful little beat.

“No… not anymore. I’m sorry, I don’t have very many dreams.”

Gaster stared down at the mattress but gathered his blanket around him. 

_ “He got tired of gagging me. That is why he injured me to the point of being mute. He said I was too loud and I cried too much when he…”  _ Gaster’s hands stilled and fell back to his lap. He rubbed the front of his neck and it reminded Sans of how Red scratched at his eye socket.

Sans had nothing to say. He gave Gaster’s arm a small squeeze.

_ “I’m sorry. I shouldn’t have said that. I should be happy I cannot speak. Now nobody has to listen to me talk.” _

__ “Don’t say that, sir,” Sans said softly, scooting a bit closer to the poor monster. “Those are Asgore’s words- you’re more than what he tried to make you.”

_ “I am a coward and a failure. I couldn’t protect my own son- not even from his brother.” _

__ “You did what you had to do to survive, Gaster,” Sans said gently. “Do you think that of Red, since he couldn’t protect his own father?”

Gaster began to sign something to argue, Sans knew it, but his hands fell away as he seemed to think about the question.

“A coward would have given up a long, long time ago. You’re very brave, sir. You and Red are both more brave than I can even comprehend, and I’m very smart!”

Gaster said nothing. Sans put a hand on his shoulder and tried to give him a smile.

“What matters is that you both survived, and you’re both here now. You’re safe.”

Sans made sure his movements were slow and deliberate, but he wrapped his arms around Gaster. It took a moment, but his arms hesitantly found their way to Blueberry’s back.

It was progress, even if it made Sans’s soul ache.

 

That night, Sans and Red were sleeping in their shared room when there came a gentle knock at the door. If Sans hadn’t been awake, he probably wouldn’t have woken up. Red didn’t stir.

“Come in,” Sans called, folding the book he’d been reading and sitting it on his night stand. His voice caused Red to blink awake, but he just looked a little curious.

For a moment, nothing happened. Sans was just about to get out of bed to go and answer the door when the handle gently turned and Papyrus’s head poked through the crack. He was on edge immediately- Papy looked very serious.

“Hey, uh… so, Red, I think you’d better come help your dad out,” he said, worry making his voice tight. 

“What’s wrong?” Sans asked.

“He’s in the kitchen, he…”

Red was already up and out of bed. He moved past Papyrus in only his boxers, having finally taken Sans’s advice to not sleep in his clothes.

Sans got out of bed and went to his brother. Papyrus was staring at the floor, and he reflexively hugged his brother when Sans got closer.

“What happened?” Sans asked as he heard Red’s quiet footsteps going down the stairs.

“He, uh… he isn’t havin’ a very good time,” Papyrus said gently, pulling away from Sans. “We should go down… in case he needs something.”

Sans was morbidly curious, but he followed his big brother down the stairs with anxiety building in his ribcage. As they reached the bottom of the stairs, Red’s voice drifted out to them.

“... it’s okay, dad. You’re here. It’s all good, he’s gone. You’re fine.”

Sans’s soul twisted as he and his brother hung back out of sight of the kitchen doorway. Sans could feel the crackle of magic in the air, tinged with fear.

“You’re here. We’re in the kitchen, with the other Sans and Papyrus, remember? Asgore’s gone. He’s never gonna hurt you again.”

Sans looked up at his brother, who seemed horrified. It sounded as though Red was going through motions- like this was not an uncommon occurrence. There was a noise of bone on tile and a rattling hiss of air.

“Shh… deep breaths… I’m right here. We’re safe. You’re safe.”

When the two brothers finally found the courage to look in the doorway, they saw Gaster curled on the floor with Red sitting closeby, gently running a hand over his skull. Gaster was crying, quiet, breathy sobs that could barely be called sobs. His eyes were wide and vacant.

Worst of all, his exposed forearm was marred with fresh wounds.

Red glanced at the two of them for a second, but then his father cried out in a warped and hissing voice and Red went back to him, keeping his hands on him and cooing gentle reassurances.

“Stay here, dad. You’re safe. I’m right here- you know I wouldn’t let him hurt you again. Listen to me, don’t think about him, okay? I’m here.”

Sans had never witnessed somebody going through an episode like this, and if the fresh wounds weren’t jarring enough, Red had to keep Gaster’s hands away from his own throat. He ket trying to claw at it.

“Sans is here, too,” Red said, looking at the shorter skeleton and motioning with his head for him to come over. 

Sans did as he was asked and very slowly sat down next to Red. Gaster’s eyes didn’t move and his magic didn’t falter. He remained curled in on himself, half propped up against the wall but mostly on the floor.

_ “Talk to him,”  _ Red signed slowly.

“H… Hello, sir,” Sans said, a bit uncertain, and Gaster’s body tensed as he spoke. “You’re going to be okay, sir, I promise. I’m right here, so is Red, we’ll keep you safe.”

Without much warning, Gaster convulsed and let out an awful, awful noise, like an animal that had been hit. Sans fell back, eyes wide and soul pounding, but Red moved closer and kept Gaster’s hands from tearing at his already-wounded neck.

“Shh, shh, come back, dad, you’re safe,” Red murmured as Sans tried to compose himself. Red’s voice was so soft and gentle. Sans had never heard him sound like that before.

Gaster was letting out hissing breaths, but as his movements stilled and the noise of his bones scraping over the floor died, he allowed Red to move forward and hold his hands.

Red hummed. For a moment, Sans was too shaken to recognize it, but as he sat he listened to Red hum a quiet little song. It sounded… familiar, almost, but in a way that he’d never known.

He got up and left, because he felt like he was witnessing something far too personal, and he’d only made it worse. Papyrus was still standing right outside of the kitchen doorway, and Sans fell into his open arms.

Red continued to hum, soft and gentle and reassuring. Sans looked up at his brother and saw him staring off into space, as though he remembered the song, too. 

They both listened to Red until the noise fell away and a short silence followed. It was Papyrus who eventually poked his head into the kitchen and saw Gaster, conscious and aware again, holding onto his son like a lifeline. His whole body was shaking.

“You’re fine, dad, it’s over. That one was pretty rough.”

Of course, there was no response, but Sans looked inside as well. Red glanced at them for a second before he gently pried Gaster away from him.

“How ‘bout we let Sans and Pap look at your arm- you cut it up pretty good.”

Gaster looked over to see the two standing uncertainly in the doorway. He looked away immediately but signed something to Red in a strange and unfamiliar sign language.

“It’s fine. They want to help-” Red reassured him gently. “They aren’t like that.”

He said something else, and Red hugged him again.

“No you aren’t, dad. We’re both a little fucked up, but it isn’t like that here.”

Gaster wiped his face and kept his head down, but Red motioned for the two monsters to come over. Sans, although still a bit off-put by how awful Gaster’s episode had been, went to him and looked over his wounds.

“Papy, can you get the first-aid kit?” he asked.

Papyrus said nothing, but he hurried over and dug in one of the cabinets until he found it.

Gaster was still shivering. Red didn’t leave his side. Sans had never really seen this side of him- protective and gentle and kind. 

“Sir, is your neck okay?” Sans asked.

_ “I’m so sorry,” _

__ Red put his hand on Gaster’s shoulder, but he didn’t say anything. He looked to Sans as though waiting for him to speak.

“Sir… you don’t have to be sorry for anything.” Sans gave him a sad smile. “All I care about is that you’re okay. I… I want to help you. We all do. You’re a part of our family now, and that means we’ll love you and support you no matter what.”

The older monster jerked his head up and stared like Sans had smacked him in the face. Papyrus brought the first-aid kit over before he knelt down beside the three of them.

“He’s right, man. We’re here for you. We want to help.”

Gaster searched both skeleton’s faces as though for a sign they were lying, but when he didn’t find it, he looked down at his shaking hands.

“See? I told you they were big saps,” Red said, but he looked at the two native skeleton’s with such a grateful light in his eyes. “Let’s get you patched up.”

 

Gaster fell asleep not too long after Sans had bandaged his wounds and made sure his neck was alright. He’d drained his already fragile magic, and the episode had exhausted him. Papyrus and his brother let Red take him to his temporary room.

He came down a few minutes later looking almost as tired as Gaster had been. He flopped onto the couch between the two other monsters and let out a deep breath.

“That’s the first flashback he’s had since we got here. Gettin’ away from our timeline has really helped him out.”

“Is he okay?” Sans asked quietly.

“He’ll be fine. Just a little rattled, heh.”

“Jesus Christ, dude… does he need to see a doctor or something? That was pretty serious,” Papyrus said as he ran a hand over his skull.

“You can ask him, but he probably won’t want to. I’ve mentioned it before. Thanks for handling this so well, though.”

Neither of the said anything, and Red’s face fell.

“I know it’s a little… hard to see. He’ll probably hole himself up for the next few days, he always does, just.. don’t baby him or anything, okay?”

“Yeah, man,” Papyrus said, but he was staring off at nothing and still seemed shaken. “He just… he really did a number on his arm.”

Red winced, and Sans instinctively leaned into him. He flashed the skeleton a grateful glance.

“Asgore really fucked him up. He had to deal with it a lot longer than I did, and Asgore… well. He was a lot worse than Papyrus. At least my brother still let me out of the house, made me keep my job, I could talk to other people, even if they all hated me. Dad… didn’t have that stuff.”

“Is there anything we can do?” Sans asked.

Red blinked. “You serious? You’ve already done a hell of a lot. He thinks you’re the nicest people this side of the universe. He loves you guys.”

“Wow, really?” Papyrus asked. 

“If he didn’t, I’d tell you. You guys being cool with him is more than enough. He just… he just needs some time.”

“He can have all the time he needs,” Papyrus said, but then he looked at Red. “You handled that really well, though. I don’t think you give yourself enough credit.”

Red looked at the ground for a second before he laughed. “Heh, sure, I guess. Happens to me, too, sometimes. It’s… it’s sort of weird, y’know? He’s all I’ve got left from home, he kept me safe when I was too young to protect myself… I don’t know how anybody like my Pap could’ve came from somebody as great as he is.”

Red was staring vacantly at the wall, but when he seemed to realize how soft his voice had gone, he blushed. 

“He’s really lucky to have you,” Sans said, wrapping his arms around Red. “We are, too.”

Red blushed deeper as Papyrus wrapped them both up in his big arms and laughed.

“I’m gonna call off work tomorrow,” Pap said, “so we can have a chill day. I think we could all use one.”

“That’s a great idea, brother,” Sans agreed, pressing his face against Red’s in a short kiss. “Family bonding time.”

It felt good to say it. That’s what they were- all four of them. A family.

  
__

**Notes for the Chapter:**

> Both underfell dudes have problems with PTSD and psychosis, latter runs in the family. Gaster is a lot more traumatized and has more frequent episodes, but when Red's hit they hit hard and he has a very hard time differentiating between his psychosis and reality.


	3. Chapter 3

**Notes for the Chapter:**

> its literally been almost two years haha
> 
> this was a sponsored chapter! if there's anybody still around on this long-dead series, enjoy this tidbit~

 

Things settled down after the first major incident. It had apparently put Gaster’s mind at ease, to some extent, to learn that the timeline native brothers were not angry about his condition, or his propensity to overreact. 

Sans balanced his little tray of food and went to Gaster’s bedroom door. The renovations were complete, so now Gaster had his own room that led off from the dining room. There was a hilariously long hallway connecting the two rooms, given that they’d used the shed, but it was wide and they’d hung up some pictures and put a light in. If anything, it gave Gaster a little more privacy.

“Sir? Can I come in?” Sans asked as he nudged the door with his foot, both hands occupied with the tray. He heard shuffling for a second before Gaster turned the knob and peeked out at him.

“I brought you some food, in case you’re hungry,” Sans explained a little sheepishly. Gaster blinked and looked down at the tray as if in shock before pulling the door back and allowing Sans to come in.

_ “You didn’t have to do that,” _ he signed, but Sans shook his head. 

“It’s no trouble! You weren’t awake to eat with Red and Papy before they left for duty, so I thought I’d make you something for lunch.”

Gaster looked at him for a moment before a warm, genuine smile graced his face. Sans returned it in full and sat the tray down on Gaster’s desk.

“Wow… we really need to get you some furniture in here, huh?” Sans asked, hands on his hips as he stared around the room. The plain beige walls had little to nothing on them, and the only furniture in the room was a desk, the bed, and a small nightstand. Sans hummed to himself as he took in the sorry display.

_ “It’s quite alright as-is,”  _ Gaster signed, hesitantly making his way over and sitting at his desk.  _ “It’s already much more than I had back home.” _

Sans felt the familiar little pang of sympathy he always felt when Gaster and Red brought up their lives in their own timeline. He walked over and gave Gaster a hug. The taller skeleton froze for a moment, but then he hugged Sans back. 

Sans drew away with a reassuring smile as Gaster sat down and started eating. “Well, that’s no excuse- we can go to the dump sometime and see if we can’t scrounge up some wall decorations or something. Alphys found me a pirate flag there once- we might get something good like that, too.” Sans rubbed his chin. “We could get you some plants, maybe… a nice floor lamp… some paintings for the walls! Whatever you want, sir.”

Gaster looked up at Sans from his chair.  _ “You don’t have to call me that…” _

Sans blushed. “Ah… well, you are older, and a doctor no less… but if you don’t want me to, I won’t!”

It was Gaster’s turn to blush. He stared down at his eggs and toast before he signed again.

_ “It’s fine. Nobody has ever called me that before.” _

Sans smiled idly as he walked over to the nightstand and touched the top where some paint had come off. “If you start working with Undyne, she could probably get you a computer, or at least a phone. I’m going over there tonight with Alphys, Undyne wants to do some research on my blaster form so she can help find a way to ease the physical stress it puts on our bodies. Would you like to come along?”

Gaster looked away for a moment.

“Of course, you don’t have to! And if you do, nobody will ask you to transform. We know it hurts a lot more for you and Red- but I think you’d like Undyne! She’s very passionate about her work, and since you were your timeline’s royal scientist… I thought maybe the two of you could relate.”

_ “Can I think about it?”  _ Gaster signed hesitantly. 

Sans nodded. “Absolutely! I’m leaving at five- just let me know by then what you’d like to do. I’d invite Red and Papy as well, but apparently they’ve got something planned with the dogs at Muffet’s- some kind of card tournament.” Sans shook his head. “If we get home and they’re drunk, I swear…”

Gaster huffed out a little laugh.

“Well, I’ll let you eat in peace-”

_ “You can stay,” _ Gaster signed immediately, fast enough to cut Sans off. He blushed and reached up for a second to scratch his chin before bringing his hands back down.  _ “If… if you aren’t busy, that is.” _

Sans stared at him for a moment before he grinned and sat down on Gaster’s bed- which he’d apparently made as soon as he’d gotten up. 

“I’m not busy at all, sir.”

  
  


Sans trotted along the path to waterfall. He couldn’t help his excitement- he turned back and waved to Gaster, who walked at a more reasonable pace behind him. 

“Are you alright, sir?” Blue said. 

Gaster smiled and nodded. He continued to look at the surrounding area in distrust. Sans sighed, bouncing in place while he waited for Gaster to catch up.

_ “You seem excited,”  _ Gaster signed with a soft smile. 

Sans grinned. “I am! Friends meeting friends is always exciting.”

Gaster looked away for a moment.  _ “Are you sure they’ll like me?”  _ Gaster rubbed his arm.

“Of course they will! Undyne is very  _ very  _ nice, even if she’s a little shy. And Alphys is great! She’s loud sometimes, but, she’s kind. Although…”

Gaster looked down with anxiety on his face. Sans rubbed his chin before he gently, very gently, punched Gaster’s shoulder.

“You’ll be the oldest one there! By a lot, actually. Oh…” Sans paused his walking and looked up at the taller skeleton. “How old  _ are _ you, sir?”

_ “Thirty eight.”  _

Sans blinked. “Wow! That is old.” When Gaster blushed, Sans waved his hands in dismissal. “No no, that’s not bad! I’m twenty five.”

_ “You’re older than Red,”  _ he said.  _ “He’s only twenty three.” _

Sans had to stop and think about that for a moment. In all the time Red and Gaster had spent back in his timeline, he’d never actually bothered to ask how old either of them were. He’d assumed Red was the same age as he was, since they were the same person.

“So… you ‘had’ him when you were...fifteen?” Sans asked. That was very, very young.

Gaster flinched away from the question.  _ “I… I suppose so. It was the experimentation that landed me the position of Royal Scientist, I had no idea at the time that… it would result in children. In hindsight…” _

“The past is the past… I wouldn’t worry about hindsight,” Sans said as he rested a hand on the older skeleton’s arm. He pulled his phone out of his pocket and checked the time.

“We should keep going, sir. We’re supposed to meet Alphys at the ferry soon.”

Gaster nodded. The two continued on their way through Waterfall side by side. Sans watched Gaster- his anxiety seemed to melt away as they continued through the calm darkness, the only sound their footsteps and the quiet running of water nearby. The air was a little damp- Sans wasn’t sure he could live in Waterfall for any extended period of time. It wasn’t cold enough for snow, but it wasn’t quite warm enough to be called warm. He did like the light and the sparkling ceiling stars, and from the looks of it, Gaster did too.

 

“Alright now punch it! Hit it!” Alphys cheered, hitting the air with her claws. “Woo!”

Sans groaned and skidded to a stop. “Al! I can’t punch things like this!”

She slapped herself in the face, a sort of ‘duh’ moment, because she continued to belt out that Sans would rip the practice dummy to shreds.

They were in Undyne’s lab, in a big open space the scientist had cleared for them. Gaster sat in the corner on a chair, observing, as Sans pranced around and decimated a practice dummy while in his blaster form. Undyne had some sensors and things set up to measure his magic output and such, but all Sans had to do was rip the heck out of the dummy.

Being in blaster form was always a bit of a change. It took a few minutes to get adjusted, and when that adjustment happened on smooth tile floor it resulted in a lot of tripping and thinly veiled cursing. But now he was fine, getting used to the four legs instead of two. He slashed a claw across the dummy’s chest and some cotton got stuck between his claws.

“First blood!” Alphys roared from the sidelines. “Destroy that thing, Sans!” 

Sans sighed. She was a little too into it.

“Alright, Sans, I think that’s good. I’ve got enough to work with for now,” Undyne called, much more demure than her girlfriend. 

“Should I shift back?” Sans asked, running over, slipping on the tile, and then sliding to a boney halt before the two girls. 

“Ah, probably not. I might have to take more measurements, and I don’t want you pushing yourself too far,” Undyne said, adjusting her glasses as she hunched over her laptop. “How do you feel?”

“I feel fine! I always feel fine when I’m in blaster form, it’s always when I shift back I get sore and tired.”

“Hmm, makes sense,” Alphys mused, taking a seat next to Undyne. “Even I can tell you put out a lot more magic when you’re like this.”

Sans nodded, nearly toppling himself, forgetting his head was much more heavy now. He recovered, glad nobody noticed, and looked over to where Gaster was seated a ways away, pretty much as far from the testing as possible. Sans made his way over.

The older skeleton looked scared. He shifted his body away from Sans as he approached, eyelights shrinking. Sans slowed down and sat, still a bit far from the other skeleton.

“It’s alright, sir. It’s just me,” he said, giving his best smile only to realize it probably wasn’t as comforting when he was on all fours and had a muzzle. He curled his tail up around his paws. “How are you doing over here?”

_ “I’m fine,”  _ Gaster signed quickly, but he refused to meet Sans’s eyes.

“Sir, if you want to go home, I can call Red-”

_ “I’m fine, I’m fine,”  _ he signed again. Sans wanted to go and comfort him, but it was clear Gaster was afraid of him in this form. He shifted his claws for a moment.

“Do you want to go sit down for a while? I’m sure Undyne has somewhere else you could go, if you’re uncomfortable seeing me like this,” Sans said softly.

_ “No, I’m sorry, I… it is not… are you okay?” _

Sans stared at him for a moment. Tears were gathering in his sockets as he clutched his pants tight, shaking.

“I’m… I’m fine, sir! I promise I’m okay, I wouldn’t lie to you or Undyne about that, I promise.”

_ “It doesn’t hurt?” _ he signed, bringing his hand up and wiping the tears away before they could fall. 

Sans made a quiet noise, wanting nothing more than to go over, but unsure if he could. He took a step. “Can I… Is it alright if I come over there, sir?” Sans asked softly. 

Gaster nodded, hugging himself tightly, still crying. Undyne and Alphys had stopped talking behind him, but Sans just hurried over and nuzzled himself close to Gaster’s chair.

“Shh, it’s alright, sir, everything’s fine,” Sans comforted. “I’m fine! It doesn’t hurt, I promise. I wouldn’t lie to you, sir.”

_ “I’m sorry- I’m sorry-”  _ he signed miserably, making Sans’s soul ache.

“It’s okay, there’s nothing to be sorry about, you’re fine. Deep breaths, sir,” Sans said. He looked up to see Undyne and Alphys watching, varying degrees of sadness and confusion on their faces. Sans nodded his head, hoping he could convey that they needed a little privacy. 

Undyne nodded and quickly grabbed Al’s arm, whispering something to her before she drew her away, off to another part of the lab.

_ “I’m sorry- I didn’t mean to do this-”  _ he signed as he sobbed. Sans was upset he couldn’t hug the skeleton, so he nestled his head against his chest, and Gaster’s arms reflexively came up and hugged him around the neck.

“It’s okay! It’s okay, sir, nobody’s angry or upset about it. I just… I don’t understand what’s wrong,” Sans said, drawing away for a moment to look into Gaster’s face. 

_ “I don’t know. I don’t know, seeing somebody else like this makes me… I’m thinking about him.” _ Gaster looked away and tried to quell his tears.  _ “I’m sorry.” _

Sans could only guess he was speaking of Asgore. He let out a deep breath and took a step back, calling on his magic for a moment and bracing himself for the moment of white hot energy as he shifted back. 

He nearly fell down, but Gaster caught him. Sans shook his head and stared up at the older skeleton, who was looking down at him like he’d dust any moment. 

“I’m fine, I’m okay,” Sans said, standing up on his own. Gaster quickly reached down and picked up Sans’s shirt, which he’d taken off before shifting, and helped the much smaller skeleton into it. Thankfully the sweatpants had remained intact.

“Phew! That’s a workout in itself,” Sans said, trying to lighten the mood, but Gaster was still shaking. Sans made a sad noise in the back of his throat and gathered the sad older man up in a hug.

“I’m here, sir. Nobody’s angry, you’re going to be fine,” he reassured, reminded of all the times he’d done this for Red. He patted Gaster’s back. “Just take deep breaths, breathe.”

Gaster whimpered roughly. He was quivering like a leaf in a windstorm. 

“Sir?”

Gaster pulled away and his hands were up at once.

_ “Can I go somewhere and relax?” _

“Of course! I’ll go ask Undyne if she’s got a comfy couch anywhere, you should go lay down and chill out.”

Gaster nodded. Sans helped him along as they walked towards where the girls had disappeared. 

“Undyne! Can Gaster go relax somewhere?” Sans called. There was some shuffling and the sound of skidding shoes, and suddenly Undyne appeared from one of the doors in the hall, Alphys quick behind her.

“Yes! Of course, follow me, s-sir,” Undyne stuttered at once. She adjusted her glasses while Alphys put a hand on her hip.

“C’mon sir, there’s a room back in the back that I nap on. It’s got a blanket and everything.” Undyne held out her hand. Gaster looked to Sans in worry, but the smaller skeleton just nodded his head and nudged him in her direction.

“Go ahead, sir, Alphys and I will be right out here working. Yell if you need anything!”

Gaster gave a tiny nod and hesitantly took Undyne’s hand. She smiled, probably in her most reassuring way, and took him back to somewhere quieter where he could relax.

Sans stared after him, a bitter sadness in his chest. What he wouldn’t give to take away a shred of the man’s torment.

“He gonna be okay?” Alphys asked, watching the two of them go. Sans nodded.

“I’m sure he will be, he just needs to calm down. I guess seeing our blaster forms really stirs him up.”

“Hm.” Alphys turned and held up her hand for a high five. “Well, let’s get training! Nothing like gettin’ sweaty and workin’ hard to get your mind off of stuff!”

Sans smiled and opened his mouth to reply when suddenly the lights went out. There was a shriek- irrefutably Undyne’s- and a surge of magic that made Sans’s whole body shudder.

The skeleton looked at Alphys for a split second before both of them ran after the scream.

“Undyne, babe! What happened, are you-” Alphys shouted as she burst through the door they’d gone in, back a ways down the hallway, but the question died on her tongue the moment she and Sans saw what had happened.

An enormous, scarred blaster was hunkered in the room, nearly too big to fit in the space. He was shuddering and whining while poor Undyne was pressed to the wall, eyes wide and scared.

Gaster. Sans swallowed the horror in his throat, taking the monster in. He was… he was  _ huge! _ He had to be some twelve feet tall- tall enough that the spines on his back touched the ceiling, making him bend and twist to try and fit into the small room. 

“O-Oh my god,” Sans said, going to Gaster’s head at once. He couldn’t even reach his arms all the way around- but the monster didn’t fight him as he hugged his snout and ran reassuring hands over his bones.

He barely noticed Undyne and Alphys escaping the room. Gaster opened his massive eyes, his claws clattering on the linoleum floor as he shook. He was crying.

“Shh, shh, I’m here. It’s okay,” Sans said, trying and failing to wipe the moisture away. “Everything’s fine- you’re fine.”

Gaster whined. The noise sounded so loud, compared to how quiet he usually was. Sans realized with a pang that he wouldn’t be able to sign like this. He pulled away from his huge skull for a moment.

“Are you hurting? Is there any pain?”

Gaster didn’t do anything for a moment, but soon shook his head. He scrabbled on the floor as he tried to adjust to the tight space, his claws leaving scrapes from their sheer size.

“Okay- okay,” Sans said, completely at a loss. He was just so big- he would have never guessed Gaster would look like this in blaster form. 

A low whimper made Sans sigh and hug Gaster’s snout again.

“You’re fine. Everything’s going to be okay- why don’t you try and lay down? That might save a bit of space.”

Gaster tried. He twisted and turned, his claws dug into the floor, and eventually he succeeded in laying down, tail curled around himself. His body took up all the space in the room except for the door- Sans had to move the small sofa out of the way.

He looked miserable. 

“Is there anything we can do?” Alphys asked. 

“I… I don’t know,” Sans said. He looked to Gaster, but the blaster had his eyes closed while he shook.

“W-We could… call Red?” Undyne offered, wringing her hands.

“Yeah! Please do- I can… I can deal with him for now, can you two give us some space?”

The ladies nodded and scampered off. 

Sans turned back to Gaster and put his arms around his skull, stroking in what he  _ hoped _ was a reassuring manner. 

“It’s okay, sir. You’re safe- nobody’s upset. Just try to calm down, okay?”

Gaster nodded weakly. He nuzzled his massive head into Sans’s arms. The skeleton gently maneuvered himself and Gaster’s skull so he could seat himself on the floor, still running his hand along the snout.

“Don’t worry- you’ll turn back soon,” Sans said, resting against Gaster in some semblance of a hug. “I’m not going anywhere- you’re okay.”

Gaster whimpered. 

Sans stayed where he was, petting along Gaster’s muzzle and whispering condolences to him. After what felt like hours, there came two familiar loud voices echoing down the hall.

“Pops!” Red shouted as he rounded the corner and saw Gaster. He didn’t look surprised- when Papyrus came a moment later, though, he gasped.

“Aw, G, you’re okay,” Red said, scarred arms coming up and hugging his head. “I’m here- Sans do a good job keepin’ ya company?”

Gaster nodded a little bit.

“Good- I knew he would,” Red said. Papyrus hesitantly stepped into the small space left in the room, taking Gaster in.

“They weren’t lying when you said you were big,” Papyrus said. Sans shot him a look, but Gaster just whimpered in response and curled away from the monster.

“N-Not that that’s a bad thing!” Papyrus amended quickly, coming forward and shoving his hands in his pockets. “I’m sorry, Gaster, I didn’t mean it like that…”

The blaster sniffled. 

The four of them were there for quite a while.


End file.
